Attachment for dental dams.



No. 640,980. Patented Jan. 9, I900.

' M. U. NELSON.

ATTACHMENT FOR DENTAL DAMS.

{Application filed Jun 17, 1899.

(No Model.)

llwirnn @TATE PATENT Qrrron.

MARTIN O. NELSON, OF NATICK, MASSACHUSETTS.

ATTACHMENT FOR DENTAL DAMS.

SPECIFICATION forming part of Letters Patent No. 640,930, dated January 9, 1900. Application filed June 17,1899. Serial No. 720,924. (No model.)

To all whomit may concern:

Be it known that I, MARTIN O. NELSON, a citizen of the United States, residing in Natick, in the county of Middlesex and State of Massachusetts, have invented a new and Improved Attachment for Dental Dams, of which the following is a specification.

This invention or improvement relates to that class of devices adapted to be attached to and suspended from the sheet of rubber or analogous material known as a dental dam and intended to prevent moisture from getting into the cavity or upon the tooth which is being operated upon by the dentist.

The object of the device is to catch and receive scraps of gold filling which drop from the tooth and to prevent the same from being lost.

The present invention is an improvement upon an invention for which an application for Letters Patent of the United States was filed by me November 14, 1898, Serial No. 696,335; and it consists in an improved structure or arrangement of parts whereby the bar for holding the pouch or pocket and the fastening rod or pin are formed on a curve, thus allowing the contrivance by conforming to the shape of the chin to be attached to the dam with its edges higher than could be the case with the invention described in the said application, thus bringing the pouch or pocket nearer the tooth which is being operated on.

The nature of the invention is fully described below and illustrated in the accompanying drawings, in which Figure l is a front elevation showing my device secured in position to a rubber dam which has been applied to a tooth to be operated upon by the dentist. Fig. 2 is a top or plan view of the device detached from the dam. Fig. 3 is a central transverse vertical section of the device attached to the dam and locked in position thereon. Fig. 4 is a similar view showing the curved rod or pin swung up, thus allowing the device to be detached from the dam.

Similar letters of reference indicate correscraps falling from the tooth comprises a back piece B with its lower edge formed or folded up into the flap or lip 0, thereby forming a pouch, and with its upper edge formed into the pocket D, the whole being made preferably, but not necessarily, of rubber and in a single piece. The flap or lip 0 extends up in front of the back piece B and has its upper edge curved, as shown. The pocket D is also formed on a curve, as indicated in Fig. 1, said curve being such as will accommodate approximately the curvature of the chin, so thatthe upper edge of the entire structure is formed with a concave recess. Within the pocket D is laid a stiffening bar or frame of the same curved shape as the pocket. This stiffening-bar is angle-shaped in cross-section and consists of the vertical portion E and horizontal portion E. At its opposite ends it is formed with the forwardly-extending lips E, perforated to receive the opposite ends of the curved rod K. This rod or bail K is curved to correspond to the curvature of the bar E E and lies directly under and close to the portion E, swinging from the lips E through the perforations in which the ends K of said bar extend. It will be noticed that the main portion of the bar E E is within the pocket D, but that its ends or lips E project forward, so that said lips and also the swinging bar K are outside the pocket. A post L extends centrally from the lower portion of the part E of the bar through the front wall of the pocket 'D, and a socket L is secured to the bar or bail K in such a position as to look over the ball on the post L in the ordinary manner when the bail is swung down.

When the device is applied to the dam, as in Figs. 1 and 3, the bail or locking-bar holds the dam snugly between it and the portions E E of the main bar or frame, said bail being held in such position by the socket and ball L L. To detach the device from the dam, the bail is swung up into the position inclicated in Fig. 4.

Having thus fully described my invention, what I claim, and desire to secure by Letters Patent, is

1. The herein-described improved attachment for dental dams, comprising the receptacle consisting of the back piece B, flap or lip O and downwardly-curved pocketD the downwardly-curved bar or stiffener E within said pocket and provided with the outwardlyextending lips E; the curved rod or bail K having its opposite ends sustained by said lips and swinging forward and upward therefrom; and mechanism for locking the said bail to said bar E when the bail is swung down, said bail, bar E and pocket being substantially correspondingly curved, substantially as and for the purpose set forth.

2. The herein-described improved attachment for dental dams, comprising the receptacle consisting of the back piece B, flap or MARTIN O. NELSON.

WVitnesses:

HENRY W. WILLIAMS, A. N. BONNEY. 

